Hi Deb and welcome to GoY. We are a gardening forum nothing is for sale on this part of the site. You can try clicking on the Garden centre button above but given that you live in Australia you really need to source your Tamarix Tree there.

Tamarix ramocissima, aphylla and parviflora are all listed as weeds in Australia - given that's the case, I suggest you google Tamarix and the varietal name your friend wants to find suppliers in Australia. If various species grow as weeds there, they must be available as varieties for purchase, surely? There are apparently about 20 forms of Tamarix which grow as weeds there, but they're all quite different from one another, so if they're available for purchase, you need to choose carefully by getting the whole name of the plant your friend wants absolutely accurate.

If they are listed as weeds by the Australian government, they are probably illegal to sell or plant, as they are here in Arizona.